Sheave for wire cables



SHEAVE FOR WIRE CABLES Filed Dec. 12', 1931 Inn enter.

Patented Jan. 23, I934 SHEAVE FOR WIRE CABLES Herald B. Greening,Hamilton, Ontario, Canada, assignor to Galloway Engineering CompanyLimited, Hamilton, Canada Application December 12, 1931 Serial No.580,639

9 Claims.

The principal objects of this invention are to reduce to the minimum thewear and deterioration of wire cables and to devise a form of sheave,the groove of which is provided with a resilient bottom which willpermit the outward dilation of the individual wires of the cable aroundthe inner surface contacting with the perimeter of the groove of thesheave.

The principal feature of the invention con- 10 sists in the novelarrangement of a narrow strip. of rubber housed within a groovecircumferen tially arranged at the base of the cable groove and inproviding a structure of sheave in which the cable is supported on metalsurfaces at either side of the central groove.

A further and important feature consists in the novel arrangement ofrubber rings to form the side contacting surfaces to engage the sides ofthe wire cable.

In the accompanying drawing, Figure 1 is a cross sectional view of therim of a cable sheave embodying the simplest form of my invention.

of a cable sheave illustrating a modification of the invention.

Figure 3 is a cross-sectional View of a cable sheave illustrating afurther modification.

It has been ascertained by careful observation in numerous experimentsthat the maximum wear of a wire cable occurs on the inward side of thecable engaging the sheave and that much of the wear and deterioration inthe life of the cable is caused by the dilation of the small wires ofwhich the cable is constituted in the sharp bending around the sheave.This dilation takes the form of the tendency of the small loops of wireforming the spirals of the smaller composite wires forming the cable,which when the cable is bent are sprung outwardly and in the normaloperation of the cable on a steel sheave these small dilated loops arecrushed out of shape. A continuous action of this kind naturally wearsthe cable rapidly.

In the simplest form of my invention as illustrated in Figure 1 the rimof the sheave 1 has formed at the bottom of the tapering cable groove 2a narrow deep groove 3 and in this groove 3 is embedded an endless bandof rubber. This rubber is of the quality ordinarily used in the treadstock of automobile tires. It is very resilient but tough and veryeifectively resists wear. The rubber is suitably bonded and preferablyvulcanized in place and forms a bear- 55' ing for the inward surface ofthe wire cable 4 Figure 2 is a cross-sectional view of the rim as it isdrawn tightly into the sheave groove 2.

It has been ascertained that the maximum dilation of the small wires ofthe cable occur substantially in the inner centre line or in the axialplane of the cable corresponding with the radial centre of the sheavegroove consequently provision of this small rubber band in the narrowgroove permits this dilation without injury and the cable operates athigher speeds and with less injury than when operated upon 65 a solidmetal sheave.

In the form illustrated in Figure 2 the sheave rim 5 is formed withquite a deepcentral groove 6 and two annular side grooves 7. These sidegrooves are preferablyseparated from the cen- 7d tral groove by theannular narrow metal strips 8, the outward perimeters of which areshaped to fit the contour of the cross-section of the cable 9.

The inner surface of the groove 6 is preferably roughened and a circularstrip of rubber 10 of a somewhat hard quality and capable of bondingwith the steel surface is inserted therein.

A strip of rubber 11 is inserted over the rubber strip 10 and completesthe bottom of the cable seat.

. The rubber strip 11 is preferably formed of the quality of materialused for automobile tire treads and is quite resilient and resistant towear.

Rubber bands 12, which are of an L shape in cross section, are insertedinto the grooves '7 which are also roughened or knurled and the qualityof rubber oi these bands oorrespondswith that of the band 10.

Rubber rings 13 are nested into the rings 12 and are formed with thesloping inward sides 14 to form the sloping surfaces of the cable grooveof the sheave.

These several composite rings are vulcanized into the sheave rim 5 and abottom surface and I side walls of tire tread rubber stock are provided,relieving the dilation o-r kinking of the small wires and also relievingthe small wires along the sides of the cable from the detrimentalcrushing effect of the tapering walls in an ordinary steel rim. o

In the form shown in Figure 3 the sheave rim 15 is formed with a deeprectangular groove 16 and embedded in this and engaging the bottom andside walls thereof is a band of rubber 17 1Q5 of a hard quality similarto the rings 10 and 12 in Figure 2. V

A ring of rubber 18, preferably of tire tread stock, is fitted into thering 17 and embedded in this ring is a metal ring 19 preferably of U-1319 shape in cross section, presenting two metal surfaces at the bottomof the sheave groove arranged either side of a central ring of rubber20.

The ring 19 presents metal surfaces similar to the surfaces 8 shown inFigure 2 but this ring is embedded in the rubber of the ring 18 and iscushioned thereby so that the entire strain of the pull of the cable isrelieved, not only by the rubber of the ring 18 beneath the U-shapedring 19, but by the rubber forming the tapering side walls of the sheavegroove 21.

It will be understood that the various forms of the invention hereinshown and described have as their basic feature the arrangement of abody of rubber centrally arranged at the bottom of the sheave grooveprovided for the purpose as herein described of relieving the crushingeffect upon the small wires of the cable as they are dilated in bendingaround the sheave.

It is important to note that in the forms of the invention illustratedherein the actual bottom of the groove on which the cable rests isrepresented by a combined metallic and cushioning contact surface. Thecushioning surface is concentric with the curved bottom of the metal element and a continuous support of two characteristics is presented to theunderside of the cable in passing over the sheave.

' A smooth running rigid or semi-rigid foundation of a desired firmnessis thus provided for the cable while avoiding wear on the dilatedcentral inner wire strands and minimizing the destructive inwardcrushing action encountered where the cable is allowed to jamb betweentwo devised without departing from the sharply sloping sheave walls.

Several forms of application of the invention have-been herein shown andfrom these it will be readily understood that other forms may beprincipal feature as herein set forth.

What I claim as my invention is:

1. A sheave for wire cables having a circumferential groove presentingcable supporting surfaces at either side of the median plane and spacedtherefrom conforming in curvature to the cross sectional curvature ofthe cable, and an endless band of rubber embedded in the space betweensaid curved surfaces and engaging and resiliently supporting the centralinside peripheral portion of the cable without distortion coincidentwith the support of the spaced curved surfaces;

2. A sheave for wire cables formed with a circumferential groove shapedin cross sectionto conform to the cross sectional curvature of the cableand having a narrow groove arranged centrally at the bottom thereof, andan endless band of rubber embedded in said narrow groove adapted'toengage the central peripheral portion of the cable, said rubber bandbeing capable of resilient distortion under load to relieve thecompression pressure on individual wires in the cable and affordingperipheral support to the central portion of the rope coincident withand substantially equal to the support of the curved side portions ofthe cable by the'adjacent curved surfaces of the sheave. f

3. A sheave for wire cables having a circumferential groove shaped incross section to conform to the closs sectional curvature of the cableand having a narrow centrally arranged groove at the bottom thereof, andan endless band of rubber material embedded in said narrow grooveadapted to engage and support the central peripheral portion of therope, said resilient band being capable of resilient distortion underload and affording continuous support to the central portion of thecable when under compression substantially equal to the support of theadjacent curved surfaces of the sheave and permitting the temporarydeformation of the cable wires without fracture or undue wear.

4; A rope sheave having a metal rim with a central groove cut therein, aring of wear-resisting rubber stock embedded centrally in said groove,said rim having annular metal surfaces at the sides of said rubber ringpresenting exposed running contacts for the cable, said rim havingannular grooves at the outward sides of said annular metal surfaces, andrings of wearresisting rubber material embedded in the latter groovesand presenting sloping wear-resisting sides of a cable groove adjacentto the exposed annular metal contact surfaces, said annular metalsurfaces providing a positive contact with the rope to restrictexcessive pressure contact or embedment of the rope in the bottom andside rubber rings.

5. A rope sheave presenting a resilient frictional cushion contact atthe bottom and sides respectively to engage the respective portions ofthe rope, and means presenting an annular metallic contact with saidrope between said respective bottom and side resilient contacts andlimiting embedment of the rope therein.

6. A rope sheave having in combination a rim, a resilient grooved'ringof rubber carried in said rim and presenting friction and cushioncontact with the rope, and means presenting exposed metallic surfaces inthe wall of the ring groove circumfer'entially of the rim to limitpressure contact of the rope with said grooved rubber ring.

'7. A rope sheave having a resilient ring of rubber mounted peripherallythereof and presenting ito 9. A rope sheave having a resilient ring ofrubber mounted peripherally thereof and presenting a rope receivinggroove, a ring of rigid ma terial of channel cross section embedded insaid rubber ring below the groove with the channel walls disposedoutwardly and terminating substantially flush with the wall of thegroove and forming a circumferential running contact for the rope, and afilling of resilient rubber fitting in the channel of said ring of rigidmaterial between the side walls thereof and presenting a cushioningcontact to the rope therebetween.

HERALD B. GREENING.

